TBA 8.5a5 - about:tor is not the default homepage after upgrade

I'm preemptively opening this in case anyone wonders why this is happening.

This will be fixed with the next release, assuming #28685 (moved) is solved. The new preferences weren't copied because the app didn't detect it was updated because the buildid didn't change since the previous release. This was partially solved in #28640 (moved), but it wasn't entirely solved.